Derives two discrete motion models for three-dimensional (3-D) pose recovery starting from the stochastic differential equations that describe the object's motion in continuous time. The velocity is considered first as a Wiener process, which underlies the very often used constant velocity model, and second as an Ornstein-Uhlenbeck process. Analysis of the autocorrelation signal derived in experiment from visual tracking of both translational and rotational movements of a human head demonstrates that such muscular motion is better suited to modeling by the Ornstein-Uhlenbeck velocity process. The model is embedded in an iterated extended Kalman filter, which linearizes about the predicted pose and in which care is taken properly to transform the state covariance, and incorporated in a system able visually to recover and track the pose of a human operator's head. The pose is copied onto a slave electromechanical stereo camera platform alone, providing two rotational degrees of freedom, or onto the same head carried by a robot arm to give complete six degree-of-freedom mapping of the operator's movements. Accuracy and frequency response are assessed.

The following presents a standardized approach to the kinematics of a generalized stereo robot head, providing both forward and inverse kinematic solutions as well as a discussion on the head Jacobian. The paper is intended as a comprehensive tutorial and as a standard notation reference for researchers in the field of active vision.

This paper describes a system for visual telepresence that copies the motion of an operator’s head onto the neck axes of an electromechanical stereo head/eye platform. Three or more point features on the operator’s head are detected using an external static camera and tracked over time to recover the pose of the operator’s head The process of capturing images, tracking features, recovering pose, and generating demands runs at 50Hz with a latency of 23ms, with the controller and platform typically taking another 20ms to satisfy a demand. Experiments show that the system, including head platform, is able to copy head movements of up to s . The paper goes on to consider the possibility of copying individual eye movements onto the individual camera axes of the head, but simulation studies suggest that delays in the feedback will lead to unsmooth eye response.

This paper describes a system for visual telepresence that slaves the motion of an electromechanical stereo head/eye platform to that of an operator's head. Features on the operator's head are detected using an external static camera and tracked over time, using three or more features to find pose (orientation and translation) with a novel algorithm which avoids explicit recovery of the features 3D positions. The recovered pose is then transformed into demands for the pan and elevation axes of the head platform. The process of capturing images, tracking features, recovering pose, and generating demands runs at 50 Hz with a latency of 23 ms, with the controller and platform typically taking another 20 ms to satisfy a demand. Experiments show that the dynamic performance of the entire system, including head platform, is sufficient to copy head movements of up to 400/spl deg/ s/sup -1/.